Stabilization of Indian Lateritic Subgrade Soil Using Alkali-Activated Slag with Sugarcane Bagasse Ash for Sustainable Pavement Infrastructure

Abstract

This research investigates the feasibility of using alkali-activated ground granulated blast furnace slag (GGBS) and sugarcane bagasse ash (SCBA) to enhance the stability of lateritic soil subgrades. The optimal maximum density was attained by conducting a series of compaction experiments using different amounts of SCBA while keeping the slag dose constant at 10% of the soil’s weight. The alkali-activator aqueous solution was produced using caustic soda (NaOH) and water glass (Na2SiO3). Both unstabilized and stabilized soil combinations underwent testing using the unconfined compressive strength (UCS) and California bearing ratio (CBR) methods. The experimental results demonstrated that the strength of the subgrade soil exhibits an increase when SCBA is added, up to a certain threshold of 10%. However, above this threshold, the strength declines. These findings were seen under a uniform amount of 10% slag. An examination of the microstructure was conducted to get insight into the extent of hydration achieved using alkali-activated binder (AAB) stabilization. A correlation was established between the strength parameters (UCS and CBR), enabling the creation of a basic linear regression model to analyze the link between these strength metrics of AAB-stabilized lateritic soil. Extended CBR and UCS testing (up to 56 days) demonstrated improved mechanical performance. This research further presents a pavement design that follows current national requirements for low-volume pavements. It showcases a notable decrease (17%) in the overall thickness of the pavement while still maintaining its performance. A comprehensive cost exploration comparing the traditional and modified pavement design demonstrated the economic benefits of using stabilization in rural pavement construction while also maintaining the sustainability component.

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